Meat quality of lambs fed crude glycerin as a replacement for corn

The objective was to evaluate the effect of increasing levels (0, 6, 12, and 18 %) of crude glycerin replacing corn in the diet of lambs on the chemical composition, physicochemical parameters, and fatty acid profile of the meat. Forty male non-castrated Santa Ines crossbred lambs with an initial average weight of 21.0 +/- 0.8 kg were distributed in a randomized block design, according to initial weight, with four treatments and ten repetitions, and slaughtered after 66 days. There was a quadratic effect (P < 0.05) on moisture, crude protein, ether extract, and an ash content of the lambs' meat with the replacement of corn by crude glycerin, with maximum values estimated in 9.77, 10.45, 9.49, and 10.73 % of crude glycerin. The physicochemical parameters were not influenced of corn by crude glycerin. The content of the fatty acids capric, lauric, myristic, palmitic, stearic, and palmitoleic linearly decreased, whereas the content of pentadecanoic, heptadecanoic, transvaccenic, oleic, CLA, a linolenic fatty acids increased with the inclusion of crude glycerin. There was a quadratic effect (P < 0.05) on the fatty acids margaric, cisvaccenic, linoleic, arachidonic, eicosapentaenoic, and docosatetraenoic with maximum values estimated in 9.90, 11.30, 10.43, 11.50, 8.83, and 7.83 % levels of crude glycerin, respectively. There was an increasing linear effect (P < 0.05) on the total content of monounsaturated fatty acids, (C18:0 + C18:1 omega 9)/C16:0, the hypocholesterolemic: hypercholesterolemic ratio, the thrombogenicity index, and the enzyme activity of Delta 9-desaturase C16:0 and Delta 9-desaturase C18:0 with increasing levels of crude glycerin, whereas the atherogenicity index (AI) decreased. There was a quadratic effect (P < 0.05) on the total content of polyunsaturated fatty acids, desirable fatty acids, and acids Omega 6 and Omega 3, and the Omega 6/Omega 3 ratio with the maximum point at the level of 11.07, 9.68, 10.55, 13.00, and 11.42 % of crude glycerin, respectively. Crude glycerin can replace corn up to 12% without influencing the physicochemical parameters of lamb meat and can improve the fatty acid profile and nutritional value of the meat.